I have a 1959 35' Steel Roamer. The through hulls for the head and generator are not like any on the market today. The through hull is just a couple inch pipe that is welded to the hull and is threaded on the bilge side for connection of a shutoff. The head through hull doesn't have a shutoff inline just a supply hose pushed over the threads and hose clamped. This connection scares me for two reasons one it doesn't have a shutoff and two the hose is old and cracked. Since the boat is out of the water for the winter I have decided to put a shutoff on the threaded pipe. I removed the old supply hose and had planned on buying a ball valve to screw on with teflon tape. My question is the more I read the more concerned I become. Is the pipe that was used by Roamer - National Pipe Straight Thread or National Pipe Tapered? I would think it should be NPT but I'm unsure? If it is NPT I can connect a ball valve directly to it with teflon tape and have a safe connection. I have done some internet research and cannot come up with an answer of how to tell what the thread type is. I realize new through hulls are NPS but question if this was a standard in the 50's? The generator through hull pipe has what looks like an old "garden" style shutoff threaded onto it. I would also like to replace this. Would putting a ball valve on this pipe be a bad idea. Should the pipe be discarded and a "new" through hull be put in its place? Are all roamers through hulls set up this way? It should probably also be stated that the boats condition is great to excellent by no means is this a scrap project. I want to do this correctly and maintain a safe boat for my family and many generations to come. Any help is greatly appreciated. I've been a long time side observer of this forum.